Set your crock-pot to high.
Thinly slice onions and put them into the crockpot with 1 cup of white wine and season with salt, pepper, and bay leaf.
Place the lid of the crockpot slightly off-center so steam can release. Cook on high for 6 to 8 hours, stirring occasionally. Onions should cook down completely without burning.
About 30 minutes before serving, combine Butter, cooking oil and flour and make a roux. Once the flour is a light caramel color, add stock to lightly thicken and warm. Season to taste.
Turn oven to broil.
Split onions between bowls, top with stock. Float cognac on top of stock. Top with a slice of french bread and cover in cheese.
Melt cheese under the broiler for up to 2 minutes, or until cheese is melting and just starting to brown.
Enjoy!